Marine Bacteria - do you know you're soaking in them?

Next time you head down to the beach for a swim
scientist Els Maas would be delighted if you spare a thought
for the invisible workhorses of the ocean.The NIWA
microbiologist is the only person in New Zealand studying
the processes of billions and billions of tiny invisible
bacteria in the oceans that play a crucial role in how the
planet works.

“Bacteria are major players in the ocean
but when we think about what’s important in the sea, we
tend to think of something like fish or whales. While they
are important, it’s really the bacteria that keep
everything going.

“They’re just there all the time,
breaking down anything that’s already dead and recycling
the nutrients for all the other organisms to use
again.”

To get an idea of the sheer volume of marine
bacteria, imagine a single drop of sea water. It contains
about one million bacteria, each no more than one millionth
of a metre long. And a litre can contain more than 20,000
different types of bacteria.

Dr Maas is particularly
interested in the processes bacteria use to do their job and
what controls these processes.

Take iron, for instance.
For humans consuming the right amount of iron is important
for good health. It’s the same for bacteria but there is a
limited amount of iron in the ocean and bacteria have to
compete with other organisms to get enough.

“Luckily
they’re very adaptable.”

Different bacteria do
different things but the same bacteria can also behave
differently in different environments.

For instance, in
the upper ocean bacteria exist that can use light and in
polar regions they must be able to withstand the cold. In
hydrothermal vents – where they provide all the energy for
big organisms - they need to stay alive at 350°C.

Studies
have found that following the oil spill into the Gulf of
Mexico in 2010, bacteria on the gulf beaches were able to
feed – and thrive – on a diet of oil. The oil, although
low in the nitrogen bacteria need to function, did provide
them with a rich food source resulting in a population
explosion.

One scientist commented that it was surprising
how fast they consumed the oil. “In some locations it took
only one day for them to reduce a gallon of oil to a half
gallon.”

The bacteria compensated for the lack of
nitrogen by getting it from the air – and the enthusiasm
with which they took to consuming the oil is likely to
provide valuable insight into future oil spill clean-up
techniques.

As Dr Maas says: “These guys can exist in
small numbers but when the conditions are right, or they
change by getting new genes, they just go for it.”

She
is also studying how climate change affects bacterial
processes and what any change to the acidity and temperature
of the ocean might mean in the future.

“We are
predicting that less carbon from the upper ocean will get
into the deep ocean. More and more is being recycled in the
upper ocean and at the same time producing more carbon
dioxide.When there is less carbon in the deep ocean it
affects the organisms in the deep that rely on the carbon as
a food source.

“And with more carbon dioxide in the
upper ocean, it adds to the CO2 already absorbed by the
ocean and leads to an increase in ocean acidification. Until
we make sure the microbial processes are okay, there will be
consequences further up the food chain.”

So while
you’re swimming, surfing or boogie boarding this summer
remember that all around you nature’s recycling bin is
busy taking in waste products and dead plant and algae
material before returning useful nutrients to the
environment.

“The bacteria are very important and we
don’t think enough about them,” says Dr Maas. “They
really are dealing with everything no one else wants.”

Bacteria breakdown

• Bacteria are the oldest
living organism on earth with evidence going back at least
3.5 billion years.• The largest known species of
bacteria was found in 1999 in the ocean sediments of Namibia
where cells were as large as 0.75mm.• There are more
bacteria in six litres of seawater than people on
earth.• Bacteria decompose dead things as big as
whales and as small as other microbes.• Bacteria can
communicate with each other and coordinate their
actions.• Bioluminescent bacteria produce light and
can be found in some fish.• Some bacteria can reach
puberty about 10 minutes after birth. That makes them
theoretically able to produce one billion offspring in an
afternoon.• Because they are constantly evolving, the
majority of bacterial species remain
undiscovered.• Without marine bacteria, life as we
know it would cease to
exist.

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